(i) Principle of floatation states that for a body to float, the weight W of a floating object is equal to the weight w of the liquid displaced by it i.e., W = w.
(ii) The upward force exerted by a liquid on an object exerted in it is known as upthrust or buoyant force.
It depends upon:
(a) The volume of the body submerged in the fluid
(b) The density of fluid in which the body is immersed.
(iii) (a) It will increase.
(b) It will increase.